This invention relates generally to catheters and more particularly to a detachable balloon catheter apparatus for the occlusion of arterial and arteriovenous lesions.
In the treatment of arterial lesions, and particularly those in the peripheral vascular system, traumatic vascular ruptures or fistulas traditionally require an operative procedure for repair in order that full functional capacity of the body part supplied be restored. Intracranial vascular anomalies, e.g. arteriovenous malformations (AVM), carotid-cavernous fistulas (co-fistulas) and arterial aneurysms also require extravascular operative interventions for repair and to protect adjacent vital brain structure from ischemia and destruction. Such procedures are frequently accompanied by a potentially high rate of morbidity and mortality. Thus, extravascular approaches to these problems are to a great extent unsatisfactory. Yet the only alternative of delay in such treatment is eventual irreparable damage. Recent innovations in the use of balloon catheters for intravascular non-operative treatment of these fistulas, and in one case an aneurysm, point to a potentially safe and atraumatic means of correction. In the case of the aneurysm, however, the neck portion was not occluded and this might permit eventual redevelopment of another lesion.
These lesions occur for a number of reasons. Trauma to the trunk or extremities can frequently cause arterial rupture with profuse blood loss, sometimes leading to exsanguination. Such lesions have been traditionally treated by open surgical exposure and repair by direct suturing or patching with a graft. Surgical repair of large or inaccessible vascular lesions has frequently been hampered by uncontrollable bleeding. It has been suggested, and in some cases demonstrated, that by using a balloon catheter, bleeding can be controlled intraoperatively. Nevertheless, the primary procedure is still one of open surgical exposure and repair under general anesthesia. Presently there is no way of occluding an arterial lesion or an arteriovenous fistula while preserving normal vascular potency without an operative procedure. The use of a one-unit balloon catheter with the catheter secured to the balloon at one end and leading out of the vascular lumen through an arterial puncture at the other end invariably will become complicated by the possibility of bleeding along the catheter and the risk of infection.
Carotid-cavernus fistulas, whether they be traumatic or of spontaneous origin, are usually treated by open surgical procedures in the neck or the head with thrombosis of the cavernous sinus or ligation of the carotid artery, or by occlusion of the cavernus carotid artery by balloon catheters. These procedures invariably result in the sacrifice of the internal carotid artery with the potential result of paralysis or even death. If left untreated, however, these fistulas can lead to blindness due to hypoxia to the retina.
Arterial aneurysms and arteriovenous malformations are usually congenital in origin and they are treated by extravascular and intravascular approaches. The extravascular approach is primarily an operative procedure called a craniotomy in which the arteriovenous lesion is removed or the arterial aneurysm occluded. Such procedures are very complicated and hazardous even in the best hands and especially in poor-risk patients. If left untreated, however, such lesions will eventually rupture, dooming the patient to disability and death. The introvascular route thus has been explored in the search for a safer and simpler therapeutic alternative. The intravascular route involves embolization of these lesions with an embolus or balloon carried to the lesion by the blood stream.
Studies have shown that an embolus/balloon at the end of a delicate, flexible catheter can be carried by the bloodstream to an aneurysm or arteriovenous malformation and be lodged there. These studies have particularly shown that an embolus held stationary at the intraluminal orifice of an aneurysm will be forced into the aneurysm and impacted there by the local hydrodynamic forces. In the case of the aneurysm, however, close examination of this means of treatment reveals that often the entire pathalogical process fails to be excluded from the normal circulation. In fact, frequently the weakened neck portion of the aneurysm remains open to the main circulation and continues to be subjected to the unceasing pulsating forces of the bloodstream. Thus, the exposed neck segments with their inherent defects can eventually expand to form another aneurysm or aneurysms capable of rupture, sometimes many years after the initial treatment. Therefore, none of the available techniques or means can reliably occlude these lesions from the main circulation safely, promptly and without an extensive operative procedure, while preserving the normal circulation.